php生成小图_php 生成缩略图代码

# 显示图形及连接

 function showdir ($adirectory, $i)

{
  global $browsedir;

  $start = $i;

# 更改 $maxcols 及 $maximages 可改变每一页显示的小图的行数与列数。

  $maxcols = 2;
  $maximages = 6;
  $maximages = $i + ($maximages - 3);

# 更改 $imagemaxwidth 及 $imagemaxheight 可改变显示小图的宽度与高度。

  $imagemax;
  $imagemax;
   
# 计算高度与宽度的比例。

  $imagemaxratio =  $imagemaxwidth / $imagemaxheight;
   
  $ndirectory = sizeof ($adirectory);
  echo (table_start);
  for ($i; $i<=$maximages;)
  {
     echo (row_start);
     for ($icols=1; $icols<=$maxcols; $icols++)
     {
       echo (col_start);
       $imagefilename = $adirectory[++$i];
       if (strlen($imagefilename)>0)
       {
         $imagepath = $browsedir."/".$imagefilename;
         $imagesize = getimagesize ($imagepath);
         if ($imagesize)
         {
           $imagewidth = $imagesize[0];
           $imageheight = $imagesize[1];
           $imageratio = $imagewidth / $imageheight;
           if ($imageratio > $imagemaxratio)
           {
              $imageoutputwidth = $imagemaxwidth;
              $imageoutputheight = ceil ($imagemaxwidth/$imagewidth*$imageheight);
           }
           else if ($imageratio < $imagemaxratio)
           {
              $imageoutputheight = $imagemaxheight;
              $imageoutputwidth = ceil ($imagemaxheight/$imageheight*$imagewidth);
           } else
           {
              $imageoutputwidth = $imagemaxwidth;
              $imageoutputheight = $imagemaxheight;
           }

# 显示图形

           echo (a_start.$imagepath.a_close);
           echo (img_start.$imagepath.img_width.$imageoutputwidth.img_height.$imageoutputheight.img_end);
           echo (line_break.$adirectory[$i]);
           echo (a_end);
         }
         echo (col_end);
       }
     }
     echo (row_end);
  }
  echo (table_end);
pagemenu ($browsedir, $ndirectory, $start);

}

function pagemenu ($browsedir, $ndirectory, $pg) {

echo "

page:";

$pg_num = 1;

for ($img_num = 0; $img_num <= $ndirectory;) {

    if ($pg == $img_num) {
    echo " *$pg_num ";
    } else {
    echo " $pg_num ";
    }

# 建立其他页次的连接, 每页显示四张图, 故页数 $pg_num 每加 1 , $img_num 就加 4 。

    $pg_num = $pg_num + 1;
    $img_num = $img_num + 4;

}

echo " ";

}

function dirtoarray ($browsedir, $extensions)
{

  $nextensions = sizeof ($extensions);
  $idirectory = 0;
  $directory = dir($browsedir);
   
  while ($entry = $directory->read())
  {
      for ($i=1; $i<=$nextensions; $i++)
      {
         $compare = stristr ($entry, $extensions[$i]);
         if (strlen($compare) == strlen($extensions[$i]))
         {
            $adirectory[++$idirectory] = $entry;
            break;
         }
      }
  }
  $directory->close();
  return $adirectory;
}

#主程序

#变量 $browsedir 为图形文件放置的位置。

$browsedir="./images";

# 允许浏览的图形文件扩展名, 放置於数组中, 可自行增加。

$extensions[1] = "jpeg";
$extensions[2] = "jpg";
$extensions[3] = "gif";
$extensions[4] = "png"; 
showdir (dirtoarray ($browsedir, $extensions), $start);

define ("line_break", "
");
define ("table_start", "

");
define ("table_end", " ");
define ("row_start", "  ");
define ("row_end", "  ");
define ("col_start", "         ");
define ("col_end", "    ");
define ("img_start", "");
define ("img_width", " width=");
define ("img_height", " height=");
define ("a_start", '');
define ("a_end", "");
?>